Trimerus (Ramiotis), 2005

Sandford, Andrew C., 2005, Homalonotid trilobites from the Silurian and Lower Devonian of south-eastern Australia and New Zealand (Arthropoda: Trilobita: Homalonotidae), Memoirs of Museum Victoria 62 (1), pp. 1-66 : 12-14

Subfamily Homalonotinae Chapman, 1890

Genera and subgenera included. Homalonotus König, 1825 , Trimerus (Trimerus) Green, 1832 , Trimerus (Ramiotis) subgen. nov., Trimerus (Edgillia) subgen. nov., Digonus Gürich, 1909 , Dipleura Green, 1832 , Brongniartella Reed, 1918 , Burmeisteria Salter, 1865 , Burmeisterella Reed, 1918 , Scabrella Wenndorf, 1990 , Arduenella Wenndorf, 1990, Parahomalonotus Reed, 1918 , Platycoryphe Foerste, 1919 , Wenndorfia gen. nov.

Discussion. Classifications of the Homalonotinae by Reed (1918), Sdzuy (1959), Tomczykowa (1975), Thomas (1977) and Wenndorf (1990) have variously emphasised particular features of the exoskeleton including glabellar lobation, glabellar outline, the course of the cephalic suture, the length of the preglabellar field, the morphology of the anterior cephalic margin, the shape of the rostral plate, the expression of a rostral process, eye position, pygidial outline, the outline of the pygidial axis, and the expression and degree of pygidial segmentation as characters of generic significance. Differences between these classifications reflect different emphases on diagnostic characters. The diversity of morphologies expressed within genera is greatly enhanced by the Australian fauna and necessitates a review of current generic concepts. A new genus Wenndorfia and two new subgenera Trimerus (Ramiotis) and T. (Edgillia) are described, and revised diagnoses are given for Trimerus , Homalonotus , Dipleura , Digonus and Parahomalonotus .